Service Availability Monitoring Framework Based On Commodity Software

Abstract

The Worldwide LHC Computing Grid (WLCG) infrastructure continuously operates thousands of grid services scattered around hundreds of sites. Participating sites are organized in regions and support several virtual organizations, thus creating a very complex and heterogeneous environment. The Service Availability Monitoring (SAM) framework is responsible for the monitoring of this infrastructure. SAM is a complete monitoring framework for grid services and grid operational tools. Its current implementation tailored for a decentralized operation replaces the old SAM system which is now being decommissioned from production. SAM provides functionality for submission of monitoring probes, gathering of probes results, processing of monitoring data, and retrieval of monitoring data in terms of service status, availability, and reliability. In this paper we present the SAM framework. We motivate the need from moving from the old SAM to a new monitoring infrastructure deployed and managed in a distributed environment and explain how SAM exploits and builds on top of commodity software, such as Nagios and Apache ActiveMQ, to provide a reliable and scalable system. We also present the SAM architecture by highlighting the adopted technologies and how the different SAM components deliver a complete monitoring framework.

Distributed Monitoring Infrastructure for Worldwide LHC Computing Grid

“…Availability computation gathers the service status information to compute the fraction of time the service was up (in OK state) during the period the service was known. Unlike availability, reliability does not consider scheduled downtime in the service known period [3].…”

“…SAM is a complete monitoring framework for grid services deployed and managed for distributed environments. It provides two main services: SAM-Nagios, a regional scheduler of monitoring probes supporting local configuration and storage/visualization of probe results; and SAM-Gridmon, a central aggregator of monitoring data and computation engine providing multiple interfaces that exposes curated monitoring results [3].…”

Infrastructure Monitoring for Distributed Tier1: The ReCaS Project Use-Case

“…Service Availability Monitoring, SAM [8] is a system developed for monitoring, at different level, services (based on grid and cloud paradigms) in EGI distributed infrastructure. The advantage of SAM is that it is integrated with other systems used for sites operations in EGI context and numerous sensors have been developed in ad-hoc manner.…”

Monitoring of services with non-relational databases and map-reduce framework

“…It ensures feedback on the quality of services delivered by the sites and identifies and helps to mitigate outages caused by middleware failures. For WLCG and EGI, this is performed by the Service Availability Monitoring framework, a well established monitoring platform that computes the overall availability and reliability of services [4].…”

“…1 shows how SAM-MR extends the existing architecture and how it connects to the existing SAM components. Distributed model of SAM currently provides two deployment models: a centralized instance that computes overall availability and reliability and a set of regional instances that gather data from WLCG experiments and National Grid Initiatives (NGIs) [4]. Both models are connected to a message bus that offers efficient transport of data between all the instances.…”